North Korea said Wednesday it regretted the deadly flood caused by the sudden release of water from a dam on the border last month, another positive sign from the North on a road toward dialogue littered with mixed signals.

The announcement, made during talks on flood control with South Korean officials, came as US officials visiting China said the US and Beijing were cooperating well in dealing with North Korea.

South Korea had demanded an apology and explanation for the Sept. 6 flash flood on the Imjin River that killed six South Koreans, caused when the North released millions of tons of water from the Hwanggang Dam north of the border without warning. The sudden flood swept away South Koreans who were camping or fishing downstream.

The Korea Herald reports the North expressed regret for the flood Wednesday and paid condolences to the victims' families, explaining officials had opened the dam's gates because of an emergency, "to prevent a bigger catastrophe."

"Literally speaking, the North expressed regrets and condolences," the official [from South Korea's Unification Ministry] said, "But in the general context, we think it's an apology by North Korea with regard to this incident."

The apology was another good sign after a month of potentially positive indications that the North will return to international negotiations on its nuclear program. But the international community is treading cautiously amid the mixed signals the North continues to send.

Mr. Campbell […] reiterated that separate talks with Pyongyang aren't acceptable to Washington. But he sketched out what appears to be a possible compromise, where the US and North Korea hold bilateral talks first, but under the rubric of the six-party dialogue.